Elastic laminate materials are commonly incorporated in absorbent articles, especially pant-like absorbent articles such as pant diapers, sanitary pants, incontinence pants, and the like. Such articles include an absorbent unit arranged in a pant-shaped chassis and are worn in the manner of a pair of underpants. Elastic laminate materials may be incorporated as part of front and/or rear body panels and/or as elastic side panels in a pant-like absorbent article.
If the elastic film is in a stretched condition in a machine direction (MD) during bonding to the at least one nonwoven layer, the nonwoven layer can gather between the bonding sites in a relaxed condition and thus make the laminate material elastically stretchable in said machine direction. Such bonding by melt fusing, for example accomplished by thermal bonding or ultrasonic welding, may result in that apertures are formed in the film in the bond sites or adjacent thereto. This will make the elastic film and the laminate breathable, which is advantageous and increases wearer comfort in an absorbent article.
WO 2008/026106 discloses a breathable elastic laminate suitable to be incorporated in an absorbent article. The laminate includes an elastic film and a nonwoven web bonded together by melt fusing in a plurality of bonding sites while the film is in a stretched condition. Apertures are formed in the film in the bonding sites concurrently with melt fusing without substantially softening the polymer material of the nonwoven web.
WO 2009/138887 discloses a method for forming a latent elastic composite from a multilayered elastic film laminated to a nonwoven facing. The elastic multilayered film is stretched in the machine direction at a stretch ratio from 1.5 to 7.0, thereby forming a stretched elastic film. The stretched elastic film is allowed to relax to achieve a relaxation percentage of at least 10% and is then laminated to the nonwoven web facing in the relaxed condition.
US 2010/0139846 discloses a method for bonding elastomeric high loft substrates wherein the elastomeric high loft substrates are introduced into the bonding station in a stretched state.
The international application PCT/SE2010/050986 discloses an elastic laminate including at least one elastic film layer and at least one nonwoven layer. The elastic film and the nonwoven layer are bonded together in a bonding pattern including a plurality of bonding elements in which the film and nonwoven are fused together. The elastic film is held in a stretched state during bonding. Apertures are formed in the elastic film in close vicinity to the bonding elements caused by rupture of the film as a result by stretching. These apertures make the film breathable.
There is still a need for a method of manufacturing an elastic laminate in which the process for stretching the elastic film prior to bonding to the nonwoven web is controlled so that bonding will occur in a controlled manner. This is especially important when the stretched elastic film is bonded to the nonwoven web(s) by melt fusing in a bonding pattern, wherein apertures are formed in the film in or in close vicinity to the bonding elements.